High speed telegraphy system



Aug.11, 1931. RS HRGTER 1,818,585

HIGH SPEED TELEGRAPH! SYSTEM Filed June 11, 1929 2 Sheets-Sheet 1 O D O 9 0 O O O O O 0' O Q 0 O 0 O O O O O 0 Q 0 0 O O 0 ll u a; 11 g; [I 5! l1 6 l] l] 5; I] [1 7 [I 2: a n Eel] :i ii 9 I] :5 l] [l 10 O O o 0 0 6 0 O O 0 0 O 0 0 0 O O 0 O O O O O O O O O O 7; f2 Z; Z! I INVENTOB rmz SCHROTER ATTORN EY A"811.,1931- I F1SHROTER 1,818,585

amt SPEED TELEGRAPH! svsmu' Filed June '11.: 1929 2 Sheets-Sheet 2 o v I I 129.4 129, 5

29 y s7 39 p 40 n 5 n H! "I: I] H n H I] EE41 [I 2:42 u 43 u I] H44 I] Z 2. 9 U u 0 INVENTOR FRHZ SCHROTER ATTORNEY Patented Aug. 11, 1931 UNITED STATES rn'rl-z ar OFFICE v FRITZ SCHIBbTER, OF BERLIN, GERMANY, ASSIGNOR TO TELEFUNKEN GESELLSCHAFT FUR DRAHTLOSE TELEGRAPHIE M. B. H., OF BERLIN, GERMANY, A CORPORATION OF GERMANY HIGH SPEED TELEGRAPHY SYSTEM Application filed June 11 1929, Serial No. 370,092, and in Germany June 8,1928.

The present invention is concerned with a high-speed telegraph apparatus predicated for its operation upon the use of conversion means of the kind employed in picture transmission. Insofar as its fundamental features are concerned, this apparatus can be used both for wire lines as well as for radio, although, essentially, it is particularly suited for short-wave operation. To change the telegraphic signals into impulses of current,

a photo-electric cell (selenium cell, seleniumtellurium cell, potassium photo-electric cell, etc.) is employed at the sending end. To reconvert the incoming current impulses into signals one of the well-known inertialess light relays is used in case of photographic recording, say, a glow lamp or a Kerr cell,-

while in case of electrochemical recordin means as likewise known from electrolytic zopicture telegraphy (production of electrochemical color reactions upon specially sensitized or prepared paper) are employed.

In short-wave high-speed telegraphy, safe operations have heretofore been impeded mainly on account of the fading of the incoming signal and further becauseof atmospherics. To remedy this condition various Ways and means have bee suggested: such as, (1) electric expediencies to the end of diminishing fading and to keep the signal strength at a constant value by periodical variation of the wave-length, by the ag regation of several receivin antennae an amplitude-limiting ampli ers, and (2) several repetitions of each signal or signal element at certain time intervals and combination or aggregation of several equi-directional receiving signals to result in an ultimate recorded signal as a means to filter out or separate disturbances or strays, which have acted like signals.

For printing telegraphs as for example, by the Baudot systems, it has been previously suggested to repeat each element or constituent of a signal (or sign) combination at intervals and to cause achain of contacts to be closed by the different impulses corresponding to it, the printing current proper being caused to fiowonl through the agency of said contacts (Ver an principle), However, devices of this nature involving mechanically moved contacts and printing means and their distributers have a good deal of inertia whereby the rate of speed of the transmission is limited. The said electrical means provided to combat signal fading involve a number of drawbacks, chiefly inherent in that they raise amplification rather strongly whenever the signal strength falls off, and that inciden in a case when one or several of the ele- 4 mentary impulses have been skipped or have dropped out during fadin intervals. By virtue of the high safety 0 signal selection 7 thus attained, and the high transmission speed thus insured, it is feasible to obtain mechanical translation free from errors of the symbolic telegraphic messages into open (or decoded) letters separately from the long-distance transmission itself in a distinct working process at the receiving place, in a way as shall be shown by what follows further below. It is thus also possible to run several such translator apparatus in parallel in order that the volume of messagescoming in through the channel of the long-distance transmission may be handled withoutaccumulation and be passed on.

The invention shall be here described in I adaptation to the so-called five-unit alphabet or code in which, in well-known manner, the signal is formed and built up by a combination of a maximum of five elements or after appear from a reading of the following 106 9 upon the transmitter cell.

cording received signals;

Fig. '5 illustrates a development of the diaphragm shown in connection with the receiving apparatusof Fig. 3;

Figs. 6 and- 7 illustrate two forms of received records; and

Fig. 8 illustrates a further modification of the system shown by Figs. 2 and 3.

Referring to Fig. 1, 1 is an intermittently, or preferably, continuously travelling telegraphic tape or band which is provided along both margins with perforations to insure better guiding. The signals are punched therein or printed thereon in five-- unit combinations, according to whether transparency or reflection is used as the underlymg principle of photo-electric scanning, as customary in picture telegraphy. As shown in Fi 1, the constituent elements of each tele rap ic si al, for example, have the form 0 elongate narrow slits toallow light to pass therethrough, these slits being arranged superposed in five rows 6, 7, 8, 9, 10, and being caused to travel past light-pas- 8- sa e or illuminating slits 2, 3, 4, or 5.

he telegraphic tape should for this object consist most suitably of opa no paper. What is essential is the oblique isposition of the different corresponding elements, the

latter being at such an interval from one 40 .another, measured in the direction of travel of the strip, that between the passages of two consecutive elements of the signal in front of one and the same light-passage slit, there is provided sufiicient time in order that elements of other signals at other such slits may be allowed to act alternately.

n thismanner, at a 'ven instant, light will be allowed to pass t rough a single element to the photo-electric cell, i. e.,-'alter-' nately at slit 2, 3, 4 or 5, to which are coordinated four ad'ustable sections 11, 12, 13 and 14 of the te egraph stri 1 separated by intervals chosen at will. e operation of such an optical transmitter strip can be followed most clearly from the drawing by starting from that element of cell 8 which happens to be locatedin the rear of slit 2 (section 11). At that instant, no light will be permitted to fall throu h slits 3, 4, 5,

ow, as the ta e continues to travel in the direction of t e arrow, it is first the ele'mentof row 8 which pertains to the signal scanned in section 12 that comes to be positioned in the rear of slits 3, while all of the other slits are covered.

The next li ht scanning takes place in section 13 by t at an element in the slit row 8 moves in the rear of slit 4, while at the same time all of the other slits are covered up. When line 8 at slit 5 is finished, the scanning of the elements of row 9 begins, if these exist at all. In this manner operations proceed by that (1) at any given inst-ant onl one element is being transmitted, and (2% that each element for n light-passage slits, is transmitted n times at conveniently prearranged time intervals. The selection of four slits as here mentioned is merely by way of example, indeed, the number thereof can be chosen either smaller. or larger, according to service requirements.

One exemplification of the optical outfit I for the photo-electric. scanning of the transmitter strip or tape according to the principle underlying Fig. 1 is shown in Fig. 2. T e tape is here denoted by 25 and the same is caused to travel continuousl slits 2, 3, 4, 5 formed or recesse in the cylindrical wall of the housing 15. Snug contact of the tape is insured by guiding the latter over rolls or pulleys. These rolls denoted by 26, 27, 28 are' finely adjustable and allow of a delicate ad'ustment of the distance between the di erent scanning zones. In front of the slits 2, 3, '4, 5, glowlamps equip ed with filaments 21, 22, 23, 24, are. mounte the latter most preferably being disposed at one side and having the shape of spirals or hands in order that the real source of luminosity ma bepositioned as closely as possible to the slits in the transmitter strip and the assage-slit. The'light falling herethroug is thrown. by the agency 0 lenses 16, 17, 18 and 19 upon the p oto-electric cell 20, say, a potassium'type of hoto-electric cell, such as an Elster and Geitel cell, whereby the current impulses controlling the transmitter are generated. In case of reflection scanning instead of the scanning here suggested, the arrangement -must be modified. correspondingly, as is fundamentally know from picture telegraphy.

Fig. 3 illustrates means for receiving by the aid of photographic recording upon a band of photographic paper similar to the transmitter strip being guided by the aid of marginal perforation. This band 48, similarly to the arrangement shown for the transmitter apparatus, Fig. 2, is guided over pulleys or rollers, and is passed'opposite the illuminating-slits 37, 38, 39 and 40 which are indicated also in Fig. 5. Through these slits, from the inertialess receiverv light source, 29, 30, 31, mounted in the interiorof the housing or case, photographically active light is thrown uponthe recording strip through the lenses 32, 33,34, Each light source is controlled by the ncommg past the iao currents in a way as is well known from picture telegraphy. I

It is suitable to employ a glow-discharge lamp having a markedly actinic gas-filling, such as a mixture of argon and nitrogen, or other appropriate and known gases. However, the ultraviolet spectrum may be utilized by that the container of the lamp and also the lenses are manufactured from uviol glass, quartz or the like permitting the transmission of such rays.

The construction of a lamp useful for this purpose is shown, though only schematicaL ly, in Fig. 4, without it being intended to show dimensional relations and details of the arrangement. In the interior of the lamp bulb 29 there are two electrodes, one thereof being the glow-light (glow-discharge) cathode 30 having the form of part of a cylinder and bein insulated against the starting of glow-disc arge currents upon the inner side thereof, while the other one o is the anode 31 surrounding the former clip or bow fashion. It is not necessary in this place to furnish further details of this luminous source, its connection and control. What is only essential here is that the cathode sheet 30 is closed to form a cylinder to such an extent that, looked at from the various directions of the image-producing lenses 32-35, it presents the same surface size in order that the images thrown upon the different light-passage slits 41-44, Fig. 3, may turn out to be .of equal size. Of

. course, it is also possible to use conveniently designed Kerr cells or other light valves in lieu of the glow-discharge tube.

. Rolls or pulleys 45, 46, 47 serve the same purpose as the rolls 26-28, Fig. 2. There is further provided a rotating diaphragm 36 which exposes always only one of the slits 41-44, and of these only a part in the direction of its height correspondin to lines 6-10, so that each light impulse o the glowdischarge lamp 29 produces a blackening effect only on a very definite portion of the recording strip coordinated toan elementf Of the light-passage openings of the diaphragm 36, only four are shown, 87-40, Fig. 8, for the sake of greater clearnes s of illustration, to illustrate the change-in illumination inside the sections which correspond tothe slits 41-44.

The actual disposition of the arrangement can be seen more lucidly from Fig. 5 showing part of the development of the diaphragm 36. For the sake of clearer underj standing, the stationary slits 41-44 have only the interval of a single signal, while in reality, measured upon the strip, they may be chosen any desired multiple thereof as indicated in Fig. 1. It can again be seen from Fig. 5 that light is permitted to fall momentarily only through a single slit, and that the slits alternate. in reception in the very same way as at the sending end. In this manner, working conditions are made so that the four (or 'n many) individual or elementary impulses which each signal is sending out, is recorded and combined in an integrating manner at the same point of the receiving strip, provided that the transmitter and receiver tapes as well as the diaphragm 36 are running in synchronism. If the blackened portions for each element are not to be combined or aggregated at one and the same place of the receiving strip by exact registering of the 11. many marks,,thenit is also possible to operate in such a way that the constituent marks which transmit the element in question atintervals, are

the blackened area rather than the degree of blackening that is evaluated in the translation to be described further below. This modification in the scheme is possible by that the illuminating slits are stag ered or shown in Fig. 6 (pictures 49 of the slits of sending tape, Fig. 1), a receiving strip, based upon summation of areas according to the last-named method is illustrated in F i 7, where 50 denotes the surfaces resulting from the alining of constituent images of the slits of the transmitter strip.

Diaphragm 36 (Fig. 3) must work in analogy with the transmitter strip, i. e., continuously,if the. latter runs also nonintermittently. But if it works intermittently,

then means must be provided also at the receiving end for the object 'of'insuring intermittent change of slit and strip conveyance. Instead of an arrangement as shown in Fig. 3, it would be feasible to use an eguipment operating with as many inertialess light-sources as there are illumination slits, and in which the 'difierent light sources (glow discharge tubes, Kerr cells, etc.) are commutated by the agency of a synchronous switch. All that is then necessary is, most suitably by the aid of a suitably moved diaphragm, to limit the height or len th of the marks in conformity with lines 6, 8, 9, 10 and to alternate the lines themselves at the proper sequence.

If electrochemical recording of signals is resorted to in lieu of photographic recepalined band-fashion; but in that case it is tion, the outfit shown in Fig. 3 is replaced by an arrangement wherein proper position of the chemical marks upon the receivin tape is insured by alternating comm'utate (changed over) contacts for the passage of the current, these contacts taking here the place of the slits provided for the passage of the light.

Translation of the signal received by an equipment as hereinbefore described into printed letters may be most suitablyinsured b the same outfit as used with the Siemens hlgh-speed telegraph, in the Baudot multichannel (multiplex) telegraph or other systems for converting the current impulse combination into types of the standard alphabet. The current impulses required for p the actuationof the translator, of course, are

not produced by contact-makers 'fedwith perforatedstrips as customary in the above types of apparatus, but rather by the aid of a photo-electric exploring or scanning device which takes here the place of the said contact makers at the transmitting end.

The photo-electrically actuated translator device will vary according to whether the covering or the alining (or surface aggregation) method is used on the photographic receiving tape. The common basic principle is that, to eliminate stray, the translator element is caused to respond andoperate whenever a certain and sufiicient number of constituent impulses for each element has been recorded. For instance, if each element is transmitted six times, the proper thing probably is to so choose the responding threshold that a blackening intensity or a blackening area corresponding to the action of three recorded impulses, will result in the minimum value required for the response of the translator element. This, on the one hand, insures adequate selectance with reference to disturbances and stray inasmuch as the likelihood that stray will systematically again and again fall 'with sufiicient intensit inside the short time interval of the recor ing of the element in'question, is small enough in order that under practical conditions all chances may be precluded of three stray signals being recorded at aplace instead of genuine telegraphic impulses.

On the other hand, the correct control-of the translator is still possible in this scheme whenever three of the six individual impulses that have been sent outhave failed to arrive owing to fading. According to prevailing working conditions, of course, the

' number of constituent impulses per element and the threshold value for the photoelectric actuation of the translator apparatus (with the necessarytolerances') will have to chosen different. v

'Inbrder to insure translatlon 1n the telegraphing method according to the invention the receiving strip (which may be divide apparatus) is caused to travel past an exploring device which consecutively causes the different elements of the signal combination to act upon the photo-electric cell. The threshold of response can be adjusted, e. g., by convenient grid potential blocking of the amplifier amplifying the photoelectric current, irrespective of whether the degree or the area of blackening is evaluated. I The current impulses produced by the photo-electric cell then adjust and operate, in known manner, the relays of an ordinary translator device of the kind as found complete in present day equipments, for instance, in the Baudot or Siemens telegraphs. Between the scanning device for the translation and the translator controlling the printing means, of course, there may be a more or less long line over which the telegram coming in on a shortwave maybe reforwarded.

Fig. 8 diagrammatically shows an exemlens 52 upon the tape 48, at a rate. or rhythm so that consecutively the constituent elements of a signal are brought to be photoelectrically evaluated accordlng to the principles hereinbefore set forth. Inasmuch as the scheme is based upon the reflection of light, the photo-electric cell (selenium, selenium-tellurium or photo-electric cell) which is denoted by 51 is most suitably made of annular shape in order that a maximum .part of the reflected light may be utilized.

The current impulses produced by this cell and amplified by amplifier 61 in well-known manner are brought to act upon the relay 62, 63 which takes theplace of the standard receiving relay of a Siemens or Baudot type printing telegraph apparatus.

Otherwise, the translator device of standard type of this system is used in a practically unaltered manner. The same is designated by 59, and is here indicated merely schematically. By the relay I 63 the five selector relays are actuated in the usual manner, and the adjustment combinations of the same result during the printing process in the selected letters upon the tape 60. It goes without saying that the speed of rotation of the-diaphragm 55,'the speed of translation of the tape 48, andthe speed'of the type selector in the translator 59 must bear a certain relationship to. one another..

Patent is the following 1. In a high speed telegraphy system, the method of transmission which comprises-repeatedly transmitting each element of each signal at time separated intervals, and re-' celving and independentl recording as received each signal to pro uce the sum total of the separately transmitted impulses for each of the transmitted elements.

2. In a high speed telegraphy system, the method of transmission which comprises repeatedly transmitting each element of each signal at time separated intervals, receiving and independently recording all received,

signals for evaluating the sum total of the separately transmitted signal impulses for 'each' of the transmitted elements, and controlling from the evaluated impulses a translator apparatus for reproducing the signal combinations into open signals 3. In a high speed signalling system, the method of transmission which comprises repeatedly transmittingeach element of'each signal at time separated intervals,'recording each of the signals on a recording tape diyided into a number of sections, and utilizmg each of the sections for controlling a translating device for evaluating the sum total of the separately transmitted elements corresponding to each of the sign 4. In a highspeedtelegraphysystem, the

method oftransmission which comprises grouping each of the elements corresponding to the transmitted signals into a plurality of 'rows arranged obliquely and positioned with predetermined separation with respect to each other on a record tape, transmitting the signals from the record tape so that each element of each signal is transmitted a plurallty of t 1mes at time se'paratedintervals, and receiving and, evaluating the sum total of the received signals so as to form a received record corresponding to the sum total of the transmitted signal impulses.

5. In a high speed telegraphy system, the method of transmission which comprises grouping each of the elements corresponding to the transmitted signals into aplurality of rows arranged obliquely and positioned with predetermined separation with respect to each other on a record tape, transmitting the signals from the record tape so that each element of each signal is transmitted independently of each other signal a plurality of times at time-separated intervalsand receiving and evaluating the sum total of the received signals so as to form a received record corresponding to the sum total of the als.

plurality of independently transmitted signal impulses.

6. In a high speed telegraphysystem, a record tape having the signals for transmission arranged thereon in a plurality of rows arranged in staggered position with respect to each other, 'a light converting element for converting the signals into electric current impulses, and'means for passing the record tape before said light convertin element so that each portion of the sai record tape is adapted to influence-the said light converting element at time separated intervals and so that each-portion of the record tape will producefrom said light converting element a plurality of time separated impulses separate from the impulses produced by each other portion of the record ta e. J

In a high speed telegraphy system, a record tape having a plurality of mark ngs thereon representing a message for trans- -mission, said markings being arranged in a plurality of parallel rows and separated with respect to each other by predetermined separations, a light converting element, a

diaphragm for screenin said light converting element from sai record tape, and

.means for passing said record tape relative to said light converting element and said diaphragm so that each element on the sa d record tape separately influences the said light converting element a plurallty of times whereby electrical impulses corresponding to the transmitted signals are generated in the light converting element. a

8. In a high speed tele raphy system, means for transmitting eac element o f a series of signals a plurality of times at t1me separated intervals, means for receiving the transmitted signals, and means for indesignals, means for passing a recording surface relative to the source of production of said light impulses sogthat the light produced influences the recording surface, and a diaphragm positioned between said recording surface and said light producing means for controlling the position on the recording surface at which the generated light influences the same, whereby theiti 'me separated signalling impulses produce .on' 130 the recording surface an evaluated record 'pendently recording the received signals in element of a 'ord, means for controlling a record produc-- ing means from the received signals, means for passing a signal recording surface relative to the saidrecord producing means, and a diaphragm positioned between said recording surface and said record produc-' ing means for controlling the position on the recording surface at which the record producing means may influence the recording surface, whereby the time separated sig-' nalling impulses produce on the recording surface an evaluated record corresponding to the aggregate of the said independent and separately transmitted signalling impulses.

11. In a high speed telegraphy system, means for transmitting each element of a signal a plurality of times at time separat ed mtervals, means for receiving the transmitted signals, an inertialess light source controlled from said received signalling impulses, a recordin tapev adapted to be inuenced by the lig t generated in said light source, and a diaphragm positioned between said light source and said recording tape for controllin the position on said recording tape at which the generated light impulses are effective, whereby'the plurality of time separated signals as transmitted are'evaluated into a composite record hav- ,mg a density corresponding to the aggregate of all of the transmitted impulses.

12. In a high speed telegraphy system, a five unit record tape haying markings, corresponding to signals for transmission, placed thereon, means for converting each of the markings onthe record tape into a plurality of time separated electrical impulses, means for receiving the time separated electrical impulses roduced from the record tape,means for uti 'zing said received electrical impulses for producing light values corresponding to the received signals, a recording tape, and means associated with the recording tape for varying the position of markings produced thereon by said generated light, whereby the separated signalling impulses produce a plurality of markings on the record tape appropriately coordinated to a single area thereof.

13. In a high speed telegraphy system,a

five unit record tape having markings, corresponding to signals for transmission, placed thereon, means for convertingeach of the separate markingsmn the record tape into a plurality of time se arated electrical impulses independent of t e impulses produced from each other markin means for receiving the time separated e ectrical imulses roduced from the record tape, means or uti 'zing said received electrical impulses for producing light values corresponding to the received signals, a recording tape, and a diaphragm A associated with the 1 recording a tape for varying the position of markings produced thereon by said generated light,

whereby the separated and independent signalling impulses produce on the record tape resenting signals corresponding to themar ings on the record surface for transmission, and a diaphragm associated withthe recording tapefor varying the position at which the record tape is subjected to the light values producedby received signals, whereby the separated. and independent signalling impulses produce on the record tape an evaluated record corresponding to the sum total of all of the signalling im ulses corresponding to a single area ot the transmitted record. I

' FRITZ SCHRGTEB.

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